No offense but, there is a chance to suffer brain damage in all methods that people do. There is still a chance to suffer brain damage with SN as well, so its irrational to be afraid of getting brain damage from partial.
Also, you can search online as well for some sources, how do you think people found their sources and are now sharing them? In addition to asking around for sources this is also a viable alternative to find sources. Just make sure they sell to individuals, many companies don't allow their products to be sold to individuals.